Apparatus for automatic takeup and release of sheets

ABSTRACT

An apparatus for the automatic take up and release of sheets includes first and second bars supported by first and second bar supports, respectively, each of which has an axial guide slot for permitting the support to rotate and move radially relative to a main shaft. The bar supports are urged in a radial direction and along the slots by means of springs so as to press the bars upon the surface of a rotatable drum associated with the main shaft and may be shifted by suitable shifting means in a radial direction against the biasing action of the springs so as to release the bars from the drum, the bars, when so released, being held in such positions by stopping means.

United States Patent [191 Kojima et al.

[ APPARATUS FOR AUTOMATllC TAKEUP AND RELEASE OF SHEETS (111 3,843,114 [451 Oct. 22, 1974 3,348,288 10/1967 Tanguay et a1. 346/138 X 3 ,381,257 5/1971 Priessnetz 346/138 X 751 t:T K" 'Sh'hUth' 1 men ors 352 :1 3? 2;: as Primary ExaminerEvon C. Blunk I Assistant Examiner-Bruce H. Stoner, Jr. 1 Asslgnee: Tokyo i l Electric Attorney, Agent, or FirmOblon, Fisher, Spivak,

Kawasaki-Shh Japan McClelland & Maier [22] Filed: Mar. 8, 1973 [21] Appl. No.: 339,371 1 1 ABSTRACT An apparatus for the automatic take up and release of [30] Foreign Application priority Data sheets includes first and second bars supported by first Mar H 1972 Japan 4744429 and second bar supports, respectively, each of which has an axial guide slot for permitting the support to Sept. 19, 1972 Japan 47 93853 rotate and move radially relative to a i s a t he [521 LS Cl 271/3 271 /277 346/138 bar supports are urged in a radial direction and along 51] Im Cl B65h 5/12 the slots by means of springs so as to press the bars [58] Fieid 274/4 upon the surface of a rotatable drum associated with 29/118 the main shaft and may be shifted by suitable shifting means in a radial direction against the biasing action [56] References Cited of the springs so as to release the bars from the drum,

the bars, when so released, being held in such posi- I UNITED STATES PATENTS tions by stopping means. 2,049,917 .8/1936 Mallina 346/138 X 2,647,462 8/1953 Dell 346/138 X 15 Claims, 27 Drawing Figures 47 26 27 39 69 73 A 72 71 52 74 Ir l 41 3 1' 22 o 24 77 59' 7 75 4 79 7e 60 8 O 61 W o j 5 49V 53 b 51 56 8 67* PATENTEBBBIZZ Ian 3.843.114

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27G 26G H5 APPARATUS FOR AUTOMATIC TAKEUP AND RELEASE OF SHEETS BACKGROUND OF THE INVENTION This invention relates to any type of apparatus for automatically winding a sheet about the outer peripheral surface of a rotatable drum and, upon completion of required work, releasing said sheet therefrom and more particularly to a type adapted for facsimile system. As used herein, the term sheet" is defined to mean any soft sheet-like material such as paper, cloth or a certain kind of plastics.

For facsimile transmission, it is necessary to wind an original sheet for transmission and a recording sheet for reception about a drum provided on each side of operation before commencement of said transmissionand' thereafter take the sheets off the drums. Hitherto, such operation has been carried out either manually, or by an extremely complicated device, presenting considerable disadvantage in respect of work efficiency and cost.

SUMMARY OF THE INVENTION It is, accordingly an object of this invention to provide an apparatus of simple construction for automatically winding a sheet about the outer peripheral surface of a-rotatable drum and, upon completion of required op eration, taking it off therefrom.

Another object of the invention is to provide such an apparatus further capable of holding the sheet tightly on the outer peripheral surface of the drum.

Still another object of the invention is to provide such an apparatusfurthercapable of unfailingly holding a sheet on theouter peripheral surface of the drum, even if the sheet happens to be shorter than the peripheral length of the drum.

- BRIEF DESCRIPTION OF. THE DRAWINGS FIG. 1 is a front elevation of an automatic sheet taking up and releasing apparatus according to an embodiment of the present invention;

FIG. 2 is a cross sectional view on line 22 of FIG. 1;

FIG. 3 is an enlarged longitudinal sectional view of only the right side section of the apparatus of FIG. 1;

FIGS. 4 and 5 are cross sectional views on lines 4-4 and 5-5 respectively of FIG. 3; FIG. 5 denotes the case where the subject apparatus is out of operation;

FIGS. 6A to 6F illustrate the sequential steps of operation of the embodiment of FIG. 1;

FIG. 7 is a side view, partly in section, of a modified mechanism for lifting a holding bar;

FIG. 8 is a sectional view on line 8-8 of FIG. 7;

FIGS. 9A and 9B schematically show the relationship of the mechanism of FIG. 7 and the position of the holding bar;

FIG. 10 is a fractional front elevation of an automatic sheet taking up and releasing apparatus according to another embodiment of the invention;

FIG. 11 is a cross sectional view on line 11-11 of FIG. 10;

FIG. 12 is a fractional sectional view of the drum of FIG. 10; and

FIGS. 13A to l3I schematically illustrate the sequential steps of operation of the embodiment of FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 to 6 jointly indicate an automatic sheet taking up and releasing apparatus for facsimile system according to an embodiment of the present invention. Throughout the figures, the same parts are denoted by the same numerals. With respect to paired members, description is only given of one of them. Referential numeral 20 is a base frame having a wall 21 erected on both crosswise sides. On said side walls 21 is supported a main shaft 22 rotatable by means of bearings 23 (FIG. 3), said shaft being driven by a drive means A connected to one end thereof. To the main shaft 22 is concentrically fixed a hollom-takeupflrum 24 by fitting members 25 (FIG. 3) so as to be driven together with said main shaft 22. Close to the outer peripheral surface of the drum 24 are disposed first and second bars 26 and 27 so as to hold a sheet on saiddrum surface. These bars 26 and 27 are arranged parallel with the axis of the drum 24 and slightly apart from each other in the peripheral direction of said drum 24. The first and second bars 26 and 27 are longer than the length of the drum, the first bar 26 having a smaller length than they second bar 27 as seen from FIG. 1. In this case, it is preferred that both bars 26 and 27 have such an initial degree of flexure that the bars may press a sheet against the drum surface with uniform pressure throughout the length of the bars.

In the outer peripheral surface of the drum 24 are cut out two grooves 28 and 29 (FIG. 4) parallel with the axis of the drum 24 in the shapes corresponding to the bars 26 and 27 respectively. Between said grooves 28 and 29 is disposed an elongate projection extending parallel therewith so as to catch the forward end of a sheet brought to the drum 24. In the bottoms of the grooves 28 and 29 are embedded friction strips 31 and 32 made of, for example, rubber, which are more or less elastic and have a sufiiciently large friction coeffi- 'cient to hold the sheet firmly. On the underside of the second bar 27 are provided a similar friction strip 33 so as to cause the sheet to be tightly attached to the outer peripheral surface of the drum and another very elastic friction strip 34 made of, for example, spongy material in order to hold the rear end of the sheet.

On each crosswise side of the drum 24 are disposed a pair of bar supports'35 and 36 for holding the end portions of the first and second bars 26 and 27 respectively (FIGS. 1, 2, 3 and 5). Each bar support 35 or 36 is provided with a shallow blind cylindrical member 37, to whose peripheral wall there is fitted one end of each bar 26 or 27 by means of a screw. The bottom of said cylindrical member 37 is bored at the center with an radially extending guide slot 38 to allow the free passage of the main shaft 22. Further on the bottom of said cylindrical member 37 near one end of said guide slot 38 is fitted a screw pin 39. On the opposite side of the main shaft 22 to said screw pin 39 is provided an engagement member 40 rotatably engageable with the main shaft 22. Across the screw pin 39 and the engagement member 40 is stretched a supporting spring 41 for pulling the bar support 35 or 36 (and consequently bar 26 or 27) toward-the center of the drum 24 along the guide slot 38.

The bar support 35 has its axial position fixed by a boss 42 of the fitting member 25 and a ring 43 fixed to said boss 42, while the bar support 36 has its axial position fixed by a boss 44 mounted on the main shaft 22 and a ring 45 engaged with said boss 44. The abovementioned arrangement enables the bar supports 35 and 36 to rotate independently of the main shaft 22 and be shifted in the radial direction of the drum 24 along the guide slots 38, but prevents said supports 35 and 36 from moving in the axial direction of the main shaft 22. The bars 26 and 27 are released from the outer periphery of the drum 24, when the bar supports 35 and 36 are lifted against the force of the springs 41 (FIG.

From the top of each side wall 21 of the subject apparatus horizontally extends a projecting plate 46 so as to be positioned above the drum 24. Each projecting plate 46 is fitted with hanging stop pins 47 and 48, which engage the bars 26 and 27 respectively when the bars are lifted to the position of FIG. 5, thereby preventing the rotation of the bars 26 and 27 and bar supports 35 and 36.

The base frame is provided with shift mechanisms 49 and 50 for lifting the bar supports and 36 to release the bars 26 and 27 from the drum 24. Said shift mechanism 49 consists of a link 51 engageable with the lower ends of the bar supports 35 and a solenoid 53 for actuating said link 51, which includes a pair of L- shaped bars 55 on both crosswise sides thereof, each L-shaped bar having an engaging member 57 formed at the outer end. Similarly, the outer shift mechanism includes a link 52 and a solenoid 54 for the bar supports 36, said link 52 being also provided with a pair of L-shaped bars 56 each of which has an engaging member 58 (FIGS. 1 and 2). The L-shaped bar is indicated in a higher position than the other L-shaped bar 56 for convenience of illustration. Said paired L- shaped bars 55 and 56 are fixed to respective pairs of arms 59 and 60, which in turn are rotatably supported by a common shaft 61 fixed to the crosswise side walls 21 of the subject apparatus. The upper and lower ends of said paired arms 59 are connected by upper and lower rods 63 and 64. Similarly, the upper and lower end ends of said 'paired arms are connected by upper and lower rods 65 and 66. From the solenoids 53 and 54 reciprocably extend plungers 67 and 68, the outer ends of which are connected to the lower rods 64 and 66 respectively. The section 69 (FIG. 2) of the base frame 20 is fitted with operating tension springs 71 and 72 whose ends are fixed to the upper rods 63 and 65 respectively (FIG. 1 omits said springs 71 and 72.).

When, under the aforesaid arrangement, current passes through the solenoids 53 and 54, the plungers 67 and 68 are retracted thereinto against the force of the springs 71 and 72. As the result, the paired arms 59 and 60 and consequently the L-shaped bars 55 and 56 rotate clockwise of FIG. 2 about the common shaft 61, causing the bar supports 35 and 36 to be brought down to the position of FIG. 2, and in consequence the bars 26 and 27 to be fitted into the grooves 28 and 29 or pressed against the outer peripheral surface of the drum 24. When current stops passing through the solenoids 53 and 54, the respective pairs of arms 59 and 60 are made to rotate counterclockwise of FIG. 2 by the force of the springs 71 and 72, so that the bar supports 35 and 36 .are lifted to the position of FIG. 5 by the L- shaped bars 55 and 56. As the result, the bars 26 and 27 are released from the drum 24 and caught by the stop pins 47 and 48 to be prevented from rotation. At this time, the stop pins 47 and 48 also serve to guide the release movements of the bars 26 and 27. The solenoids 53 and 54 can be operated by a well known electric circuit (not shown).

Close to the outer peripheral surface of the drum 24 is disposed a roll 73 (FIG. 2) for releasing a sheet from the drum 24. (Said roll 73 and its driving mechanism are omitted in FIG. 1.). The roll 73 is rotatably pivoted to one end of an arm 74, which in turn is rotatably supported at the intermediate part by a shaft 75 fixed to the crosswise side walls 21 of the subject apparatus. The aforesaid section 69 of the base frame 20 is provided with a solenoid 76, from which a plunger 77 reciprocably extends outward. The plunger 77 has its forward end connected to the other end of the arm 74, and is provided with a flange 78 near the solenoid 76. Across the flange 78 and solenoid 76 is stretched a v compression spring 79.. When the solenoid 76 is electrically magnetized, the plunger 77 is pulled thereinto, causing the arm 74 to rotate clockwise of FIG. 2 about the shaft 75. At this time, the roll 73 is pressed against the outer peripheral surface of the drum 24. When the solenoid 76 is demagnetized, the plunger 77 is moved in the opposite direction to the preceding case by the spring 79 to release the roll 73 from the drum 24. The solenoid 76 can be operated by a well known electric circuit (not shown).

There will now be described by reference to FIGS. 5 and 6 the operation of a sheet taking up and releasing apparatus according to an embodiment of this invention. When the apparatus is out of operation, the respective pairs of arms 59 and 60 are pulled by the springs 71 and 72 since the solenoids 53 and 54 of the shift mechanism are demagnetized. As the result, the respective pairs of L-shaped bars 55 and 56 lift the bar supports 35 and 36 to keep the holding bars 26 and 27 apart from the drum 24 (FIG. 5). At this time, the drum 24 is brought to rest in the prescribed position by stop means (not shown). The solenoid 76 is also demagnetized to set the roll 73 apart from the drum 24,

When a sheet 80 delivered from a feed mechanism (not shown) is inserted into the groove 28 with the forward end of said sheet 80 pressed against the elongate projection 30 disposed between the grooves 28 and 29, then the solenoid 53 is magnetized to release the paired L-shaped bars 55 from the bar supports 35, which in turn are pulled toward the center of the drum 24 by springs 41, causing the first holding bar 26 to be fitted into the groove 28. At this time, the forward end of the sheet 80 is held by said bar 26 and the friction strip 31 of the groove 28, and the first holding bar 26 is disengaged from the stop pin 47, ready to rotate with the,

drum 24 (FIG. 6A).

When the drum 24 slowly rotates in the direction of the indicated arrow, the sheet 80 is pulled by the first bar 26 to have its forward portion attached to the outer peripheral surface of the drum 24. When the drum 24 completes the prescribed amount of rotation, the solenoid 54 is magnetized, and the second holding bar 27 is brought downward by the springs 41 to press the sheet 80 against the outer peripheral surface of the drum 24 (FIG. 6B). The second bar 27 which is not fitted into the groove 29 at this time projects on to the drum surface and is prevented from rotating by the stop pin 48. When, therefore, the drum continues to rotate, the second bar 27 furnishes the sheet 80 with a tension acting in the opposite direction to that in which the drum rotates, by means of the friction strip 33, enabling the sheet 80 to be tightly pressed against the outer peripheral surface of the drum 24 without giving rise to any crease on the sheet 80 and any gap between the sheet 80 and the drum surface. When the drum 24 makes a substantially full rotation, the groove 29 is brought right under the second bar 27, causing the second bar 27 to be fitted into said groove 29 by the force of the springs 41 and the rear end of the sheet 88 to be held between the friction strips 32 and 34 (FIG. 6C). At this time, the second bar 27 is released from the stop pin 48, ready to rotate with the drum 24. Thereafter the drum rotates at a high speed for facsimile transmission or reception. During such operation, the bars 26 and 27 are tightly fitted into the grooves 28 and 29 by the force of the springs 41, preventing the sheet 80 from being displaced or coming off the drum 24.

Upon completion of facsimile transmission or reception, the drum 24 is again brought to rest in the position of FIG. 6C. At this time, the solenoid 76 (FIG. 2) is magnetized to press the roll 73 against the sheet 80 placed on the drum surface. Next, when the solenoids 53 and 54 are demagnetized, the bar supports 35 and 36 are lifted by the respective pairs of L-shaped bars 55 and 56, thereby causing the first and second bars 26 and 27 to be set apart from the drum 24 (FIG. 6D). Later when the drum 24 rotates slowly, the roll 73 is driven by the drum 24, so that the sheet 80 is delivered forward by the roll '73 and drum 24 while being guided by a guide member 81 (FIG. 6E). The stop pins 47 and 48 which are disposed outside of the ends of the drum 24 do not obstruct the delivery of the sheet 88. The first and secondholding bars 26 and 27 additionally guide the sheet 80 by controlling its travel.

When the groove'29 of the drum 24 is brought immediately ahead of the roll 73, the solenoid 76 is demagnetized to separate the roll 73 from the drum 24 (FIG. 6F). At this time, the sheet 88 is held by another guide means (not shown) to be delivered to any other succeeding process than facsimile transmission. When the drum 24 is brought to rest in the position of FIG. 5, the entire facsimile operation is completed.

The shift mechanism for lifting bar supports 35 and 36 may consist of cam mechanism as seen from FIGS. 7 and 8 jointly illustrating a modification of said shift mechanism. This modified mechanism includes a sup port shaft 82 fixed to the crosswise side walls 211 of the subject apparatus and pairs of arms 83 and 84 respectively which are rotatably supported by said shaft 82. These paired arms 83 and 84 are positioned below the bar supports 35 and 36 and obstructed in making any movement in the axial direction of said shaft 82. Abutting members 85 and 86 engageable with the bar supports 35 and 36 are supported by the paired arms 83 and 84 near one end of said members 85 and 86. Cam followers 87 and 88 are rotatably supported also by said paired arms 83 and 84 near the opposite end thereof. A pair of arms 83 are connected by three rods 89 for a simultaneous movement and another pair of arms 84 are connected similarly by three rods 90 so as to be moved jointly. On the base frame is formed a raised portion 91 to which there is connected one end each of operating tension springs 93 and 94. These springs 93 and 94 are connected at the opposite end to the rods 89 and 90 respectively which are disposed below, so as to normally urge the paired arms 83 and 84 for their clockwise rotation about the support shaft 82.

On both crosswise side walls 21 of the subject apparatus is rotatably provided another support shaft 95 by means of bearings 96. Said support shaft 95 is rotated by a drive means (not shown) which is controlled by a well known control mechanism. Said support shaft 95 can freely pass through holes 97 and 98 bored in the arms 83 and 84. These holes 97 and 98 have a sufficiently large size to prevent the peripheral wall of said holes from being brought into contact with the support shaft 95 even when the arms 83 and 84 swing for operation. On the support shaft 95 are fixed pairs of cams 99 and 100 engageable with the cam followers 87 and 88. Said cams 99 and 100 each have a larger diameter section and a smaller diameter section. When said larger diameter sections abut on the cam followers 87 and 88, then the arms 83 and 84 rotate counterclockwise about the shaft 82 to be released from the bar'supports 35-and 36, causing the holding bars 26 and 27 to abut against the peripheral surface of the drum 24 (FIG. 7). When the cams 99 and 100 rotate in the direction of the indicated arrow to have the smaller diameter sections engaged with the cam followers 87 and 88, then the arms 83 and 84 rotate clockwise by the force of the springs 93 and 94 to lift the bar supports 35 and 36, causing the holding bars 26 and 27 to be removed from the drum 24 (FIG. 9A).

The cams 99 and 100 have substantially the same form, but, as seen from FIG. 7, the cam 99 is so shaped as to have its larger diameter section abut against the corresponding cam follower 87 earlier than the larger diameter section of the cam 100 engages the corresponding cam follower 88. When, therefore, the cams 99 and 100 rotate to the positions of FIG. 9B, only the first holding bar 26 engages the drum 24, with the second holding bar 27 still kept apart from the drum 24. Obviously, change of the position of the aforesaid cam mechanism to FIG. 7, FIG. 9A or FIG. 9B easily permits the operating steps of FIGS. 6A to 6E. The mechanism of FIG. 7 only requires a single support shaft 95 to be rotated according as a sheet is wound about the drum or released therefrom.

FIGS. 10 to 13 jointly illustrate another embodiment of this invention. Throughout these figures, the parts the same as those of the preceding embodiments are denoted by the same numerals suffixed by the letter a.

Since the embodiment of FIGS. 10 to 13 has the right and left sides arranged in the same manner, FIG. 10 only indicates the arrangement of the right side. In the embodiment of FIG. 10, the drum 24a may wholly consist of a permanent magnet. In such case, the drum 240 should preferably have its peripheral wall polarized in the radial direction. Where most of the drum 24a is formed of a nonconducting material, for example, ferrite, it is advised to prepare the peripheral portion of both ends of the drum 24a from a conducting material and connect said conducting peripheral portions to the earth terminal of the subject apparatus through the main shaft 22a. Further, if the drum 24a is designed to act as an electrode for facsimile reception, then the drum 24a will have its outer peripheral surface coated with a thin conducting layer.

In-the embodiment jointly illustrated by FIGS. 10 to 13, the grooves 28 and 29 formed in the outer peripheral surface of the drum 24 of the first embodiment are collectively replaced by a single fiat notch 101 extending parallel with the axis of the drum 24a. The notch 7 a 101 has the later described stepped portion formed on one lengthwise side with the prescribed thickness. Further, first and second holding bars 26a and 27a (FIG. 10) are-provided in proximity to the outer peripheral surface of the drum 24a. Said first and second holding bars 26a and, 27a are parallel with the axis of the drum 24a. and are'normally superposed on each other in the radial direction of the drum 24a. As in the preceding embodiments, said first and second holding bars 26a and 27a act to hold the forward and rear ends of a sheet respectively on the outer peripheral surface of the drum 24a. In the case of FIG. 10, the outer peripheral surface of the drum 24a isnormally polarized and the first and second holding bars 26a and 27a are formed of a magnetically sensitive material, or this arrangement may be reversed. Obviously, it is possible magnetically to polarize both drum 24a and holding bars 26a and 27a. Said holding bars 26d and 27a are supported by bar supports 35a and 36a respectively on both crosswise sides of the drum 24a, though FIG. 10 only indicates only the pair of said bar supports. Said bar supports 35a and, 36a respectively consist of upper plates 103 and 104 to which one end each of the holding bars 26a and 27a is fixed and lower plates 107 and 108 con nected to said upper plates 103 and 104 by pairs of side plates 105 and 106. Each of said upper plates 103 and 104, each of said lower plates 107 and 108 and each of the pairs of said side plates 105 and 106 collectively define a rectangular free space 38a corresponding to the guide slot 38 of the preceding embodiments, and further are fitted into 'an annular groove formed in the peripheral surface of the main shaft 22a to have their axial positions fixed. Across the screw pins 39a inserted into" the upper plates'103' and 104 and engagement members 40a rotatably engageable with other annular grooves formed in the main shaft 220 are respectively stretched supporting tension springs 41a so as to pull the first and second holding bars 26a and 27a toward the center of the drum 24a. The bar supports 35a and 36a of the embodiment of FIGS. 10 to 13 have substantially the same function as those of the preceding embodiments.

The main shaft 22a is fitted with engagement pins 109 projecting in the radial direction. Each pin 109 is so'designed as to be fitted into a'corresponding hole 110 bored in the upper plate 103 of each bar support 350, when the first holding plate 26a is pressed against the outer peripheral surface of the drum 24a. At this time said bar support 35a is prevented from rotating independently of the drum 240. In contrast, the supports 36a of the second holding bar 27a lack such device and are rendered rotatable independently of the drum 24a.

. A single shift mechanism 49a for lifting the bar supports 35a and 36a has a pair of lifting bars 55a formed into an L-shape in cross section and provided with abutting sections 57a. Said lifting bar 55a is'fixed to each of a pair of arms 59a disposed on both crosswise sides of the drum 24a. Said arms 59a have their lower ends connected to a plunger 67a of a solenoid 53a through a single rod 660 (FIG. 10). Across each of a pair of pins 111 projecting upward from the base frame 200 and the lower ends of the arms 59a are stretched operating tension springs 710 respectively. According to the embodiment of FIGS. 10 to 13, when the solenoid 53ais magnetized, the L-shaped bars 55a are released from both bar supports 35a and 36a, and when 8 the solenoid 53a is demagnetized, the L-shaped bars 55a lift said bar supports a and 36 a by the force of the springs 714. According to the embodiment of FIGS. 10 to 13, a single bar a lifts the bar supports 35a and 36a disposed on one crosswise side of the drum 24a at the same time.

A roll 730 made of, for example, rubber is rotatably pivoted to one end of an L-shaped member 112, which in turn is rotatably suupported by a support shaft a fixed to the crosswise side walls 21a of the subject apparatus. Said L-shaped member 112 is provided at the opposite end with a pin 113, which is connected to a plate spring 114 fixed to the bar 55a. When, therefore, the L-shaped bar 55a rotates so as to remove the holding bars 26a and 27a from the drum'24a, then the roll 73a is pressed against the outer peripheral surface of the drum by means of the plate spring 114 and L- shaped member 112. When the L-shaped bar 55a rotates in the opposite direction, the roll 73a is detached from the drum 24a The mechanism of said roll 73a is indicated in FIG. 11. v I

I Stop pins 115 each fitted to plates 46a horizontally projecting inward from the crosswise side walls 21a engage both of the holding bars 26a and 27a when the bars move away from the drum 24a, thereby preventing them from rotating with the drum 24a. From a solenoid 116 fixed at the upper part of each crosswise sidewall 21a hangs down an operable stop pin 117 to penetrate ahole bored in the horizontal projecting plate 46a.

When the solenoid 116 is magnetized, said pin 117 Against the underside of said large diameter section' contacts neitherof the holding bars 26a and 27a, but when the solenoid 116 is demagnetized, said pin 117 is pushed down bya compression spring 118 to abut against only the screw pin 39a of the second bar support 36a.

The horizontal plate 460 is further provided with a whisker electrode 119 whose free end is made to touch the outer peripheral surface of the drum 24a. When the whisker electrode 119 has its free end brought into direct contact with the drum surface, namely, when the rear end of a sheet leaves the whisker electrode 119,

then the solenoid 116 is magnetized by said whisker electrode 119 through a lead 120 andja well known circuit (not shown) to lift the operable stop pin 117 as later described. The position of the rear end of the sheet may be detected by a known optical means.

Referring to FIG. 12, the notch 101 cut out in the outer peripheral surface of the drum 24a is bored with a vertical hole 121 extending toward the interior of the drum 24a. A pin 122 inserted into said hole 121 has its inner end formed into a large diameter section 123.

123 abuts the free end of a spring 124 fixed to the inner peripheral surface of the drum 24a, causing the outer end of said pin 122 normally to project fromthe outer peripheralsurface of the drum 24a. When, however, the holding bars 26a and 27a are pressed to the outer peripheral surface of the drum 24a, the pin 122 is 99. .1. 10E11 dr m Z4 There will now be described the operation of the embodiment of FIGS. 10 to 13. When the subject apparatus is out of operation, the solenoid 53a (FIG. 10) remains demagnetized to keep the holding bars 26a and 27a apart from the drum 24a by the force of the operating springs 71a, said force being so designed as to be larger than a sum of the force of the supporting springs 41a and a magnetic force prevailing across the drum 24a and the holding bars 26a and 27a.

When a sheet 80a is brought to the surface of the drum 24a through a guide (not shown), said sheet 80a has its forward end stopped by the pin 122 (FIG. 13A). The whisker electrode 119 only applies a sufficiently low elastic pressure on the sheet 80a to permit its free travel.

When the solenoid 53a is magnetized, the bar supports 35a are pulled away by the force of the spring 41a, causing the bars 26a and 27a to be removed from the first stop pins 115 and abut against the outer peripheralsurface of the drum 24a. Further, the bars 26a and 27a push down the pin 122, causing the forward end of the sheet 80a to be held between said bars 260 and 27a and the notch 101 (FIG-13B). At this time, the bars 26a and 27a are tightly pressed against the outer peripheralsurface of the drum 24a all along the length without any gap left by a magnetic force occurring across said bars 26a and 27a and the drum 24a. Each of the bar supports 35a for the first holding bar 26a engages the main shaft 22a by means of the pin 109 and hole 110. On the other hand, the pin 39a of each of the bar supports 36a is held by the operable stop pin 117 due to the demagnetization of the solenoid 116.

When the drum 24a slowly rotates in the direction of the'arrow indicated in FIG. 13C, then the first holding bar 260 rotates with the drum 24a by the force of the springs'4la, while pressing the forward end of the sheet 80a to the outer peripheral surface of the drum 24a. On the other hand, the second holding bar 270 is prevented from rotation by the second stop pins 117, thereby applying a tension to the sheet 80a acting in the opposite direction to that in which the drum 24a rotates. Since the bar 27a is tightly pressed against the outer peripheral surface'of the drum'24a all along its length due to a magnetic force prevailing between said bar 27a and the drum 24a, the sheet 80a is firmly attached to the drum surface without any gap or crease.

Even if the sheet 80a happens to be shorter than the peripheral length of the drum 24a, the sheet 80a can be tightly held on-the drum surface. Following is the reason. When the whisker electrode 119 is brought into direct contact with the drum 240 the moment sheet 80a leaves said electrode 119, the solenoids 116 are magnetized to pull the stop pins 117. At this moment, the second holding bar 27a is released from the pins 117 and begins to rotate with the drum 24a while holding the rear end of the sheet 80a by the force of the spring 41a as well as by the magnetic force occurring between said bar 27a and the drum 24a (FIG. 13D). Thereafter the drum 24a is once brought to rest in the position of FIG. 13E, ready for the succeeding facsimile transmission 'or reception.

Upon completion of said facsimile operation, the drum 24a commences a slow rotation from the position of FIG. 13E. At this time, the pin 117 is again pulled downward by the demagnetization of the solenoid 1.16 to engage the pin 39a. As the result, the second holding bar 270 is brought to rest in the position of FIG. 13F, causing the sheet 80a to have its rear end released from the second bar 27a and rotate with the drum 24a. And then the first bar 26a is brought right under the second bar 27a, because the stepped section 10.2 of the notch 101 has a larger thickness than the first bar 26a (Fig. 136). At this moment, the solenoid 53a is demagnetized, causing the roll 73a to press the sheet 80a against the outer peripheral surface'of the drum 24a by means of the L-shaped bar 55a and the first and second holding bars 26a and 27a to move away from the drum by the supports 35a and 360 (FIG. 13H). At this time, the pins 109 are disengaged from the bar supports 36a and the holding bars 26a and 27a are prevented from rotation by the pins 115.

Later when the drum 24a continues to rotate, the sheet a is delivered from the drum 24a by the frictional rotation of the roll 73a with the drum 24a and conducted by the guide 81a to the succeeding process (FIG. 1). The drum 24a is again brought to rest in the position of FIG. 13A to complete the entire facsimile operation.

As previously described, the embodiment of FIGS. 10 to 13 enables the sheet 80a to be firmly pressed to the outer peripheral surface of the drum 24a, even through the sheet 80a may be shorter than the peripheral length of the drum 24a. Further, in this embodiment, the drum surface is not provided with any groove as in the first embodiment, preventing the end portion of the sheet 80a from being folded by being perchance drawn into said groove. Moreover, the holding bars 26a and 27a are attracted to the drum surface by the cooperation of the springs 41a and the magnetic force occurring across said bars 26a and 27a and the drum 24a, thereby enabling the sheet 80a to be firmly held to the outer peripheral surface of the drum 240 without any gap.

What we claim is:

1. An apparatus for automatic takeup and release of sheets which comprises:

a base frame;

a main shaft rotatably supported on said base frame;

means for driving said main shaft;

a sheet takeup drum coaxially fixed to said main shaft and rotatable about the axis of said shaft;

first sheet holding means disposed close to the outer peripheral surface of the drum to holdthe forward end of the sheet on the drum surface when said sheet is taken up thereon, and to release said forward end when the sheet is taken off the drum;

second sheet holding means provided in proximity to the outer peripheral surface of the drum to press the sheet tightly to the drum sheet and then hold the rear end of the sheet on the drum surface when the sheet is taken up thereon and torelease said rear end when the sheet is removed from the drum;

said first and second sheet holding means being first and second bars extending parallel with the axis of said drum;

pairs of first and second bar supports for supporting said first and second sheet holding bars at both ends of said drum, respectively, said supports being movable in the radial direction relative to said shaft and also rotatable independently of said drum about said shaft;

means for urging said first and second bar supports toward one side of said drum in said radial direction for pressing said first and second sheet holding bars against the outer peripheral surface of said drum; 7

a shift mechanism for moving said first and second bar supports toward the opposite side of said drum in said radial direction for releasing said first and second sheet holding bars from said drum; and means for delivering the sheet from the drum.

2. The apparatus according to claim 1 wherein there are provided stop means for preventing the rotation of the second sheet holding bar when said bar is pressed against the outer peripheral surface of the drum.

3. The apparatus according to claim 2 wherein a groove is formed in the outer peripheral surface of the drum to extend along its axis in a shape corresponding to that of the second sheet holding bar, said second bar being released from the stop means when inserted into said groove.

4. The apparatus according to claim 2 wherein there are further provided means for generating a signal upon detection of the position of the rear end of the sheet and means for releasing the stop means from the second sheet holding bar upon receipt of said detection signal. 1

5. The apparatus according to claim 1 wherein the shift'mechanism includes a link system.

6. The apparatus according to claim 1 wherein the shift mechanism includes a cam mechanism.

7. The apparatus according to claim 1 vwherein at least oneof, said first and second sheet holding bars, and said drum, is magnetically polarized.

8.'The-apparatus according to claim 1 wherein the meansfor delivering the sheet includes a roll frictionally pressed to the drum surface when the sheet is taken off thedrum.

9. An apparatus for automatic take up and release of sheets which comprises:

a sheet take up drum coaxially fixed to a rotatable shaft and in which a first longitudinal bar holds the forward end of said sheet upon the drum surface and a second longitudinal bar presses said sheet tightly to said drum and retains the rearward end of said sheet upon said drum surface when said sheet is taken up thereon, said first and second bars releasing said both ends of said sheet when said sheet is to be removed from said drum;

pairs of first and second support members for supporting the ends of said first and second bars at said both ends of said drum respectively;

said support members each having a radially extending guide slot through which said shaft passes and which permits the associated support member to rotate and move radially relative to said shaft;

supporting spring means for imparting tension to said first and second support members along said guide slots for pressing said first and second bars to said drum surface;

means for shifting said first and second support members along said guide slots against the supporting spring means for releasing said first and second bars from said drum surface; and

stopping meansvdisposed near said drum surface forholding said first and second bars in position and thereby preventing the rotation of said bars when said support members are shifted by said shifting means.

10. An apparatus according to claim 9 wherein; said drum surface is provided with first and second longitudinal grooves for accommodating said first and second bars respectively; and

said stopping means has first and second stop pins for engaging said first and second bars respectively,

whereupon said second bar may be released from said second stop pin when said second bar is inserted into said second groove.

11. An apparatus according to claim 9, wherein said stopping means has an operable stop pin ,for holding said second bar until said rearward end of said sheet is disposed below said second bar.

12. An apparatus according to claim 11, wherein there is further provided:

means for generating a signal upon detection of the position of the rearward end of said sheet; and means for releasing said operable stop pin from said second bar upon receipt of said detection signal.

13. An apparatus according to claim 9, wherein there is further provided a roll for delivering said sheet from the drum, said roll being connected to said shifting means and adapted to be frictionally pressed to said drum surface when said shifting means shifts said support members.

14. An apparatus according to claim 9, wherein said shifting means includes:

operating spring means for urging said first and second support members against said supporting spring means when said support members are shifted; and

actuating means for releasing said shifting means from said first and second support members against said operating spring means.

15. An apparatus according to claim 9, wherein at least one of, said drum, and said bars, is magnetically polarized. 

1. An apparatus for automatic takeup and release of sheets which comprises: a base frame; a main shaft rotatably supported on said base frame; means for driving said main shaft; a sheet takeup drum coaxially fixed to said main shaft and rotatable about the axis of said shaft; first sheet holding means disposed close to the outer peripheral surface of the drum to hold the forward end of the sheet on the drum surface when said sheet is taken up thereon, and to release said forward end when the sheet is taken off the drum; second sheet holding means provided in proximity to the outer peripheral surface of the drum to press the sheet tightly to the drum sheet and then hold the rear end of the sheet on the drum surface when the sheet is taken up thereon and to release said rear end when the sheet is removed from the drum; said first and second sheet holding means being first and second bars extending parallel with the axis of said drum; pairs of first anD second bar supports for supporting said first and second sheet holding bars at both ends of said drum, respectively, said supports being movable in the radial direction relative to said shaft and also rotatable independently of said drum about said shaft; means for urging said first and second bar supports toward one side of said drum in said radial direction for pressing said first and second sheet holding bars against the outer peripheral surface of said drum; a shift mechanism for moving said first and second bar supports toward the opposite side of said drum in said radial direction for releasing said first and second sheet holding bars from said drum; and means for delivering the sheet from the drum.
 2. The apparatus according to claim 1 wherein there are provided stop means for preventing the rotation of the second sheet holding bar when said bar is pressed against the outer peripheral surface of the drum.
 3. The apparatus according to claim 2 wherein a groove is formed in the outer peripheral surface of the drum to extend along its axis in a shape corresponding to that of the second sheet holding bar, said second bar being released from the stop means when inserted into said groove.
 4. The apparatus according to claim 2 wherein there are further provided means for generating a signal upon detection of the position of the rear end of the sheet and means for releasing the stop means from the second sheet holding bar upon receipt of said detection signal.
 5. The apparatus according to claim 1 wherein the shift mechanism includes a link system.
 6. The apparatus according to claim 1 wherein the shift mechanism includes a cam mechanism.
 7. The apparatus according to claim 1 wherein at least one of, said first and second sheet holding bars, and said drum, is magnetically polarized.
 8. The apparatus according to claim 1 wherein the means for delivering the sheet includes a roll frictionally pressed to the drum surface when the sheet is taken off the drum.
 9. An apparatus for automatic take up and release of sheets which comprises: a sheet take up drum coaxially fixed to a rotatable shaft and in which a first longitudinal bar holds the forward end of said sheet upon the drum surface and a second longitudinal bar presses said sheet tightly to said drum and retains the rearward end of said sheet upon said drum surface when said sheet is taken up thereon, said first and second bars releasing said both ends of said sheet when said sheet is to be removed from said drum; pairs of first and second support members for supporting the ends of said first and second bars at said both ends of said drum respectively; said support members each having a radially extending guide slot through which said shaft passes and which permits the associated support member to rotate and move radially relative to said shaft; supporting spring means for imparting tension to said first and second support members along said guide slots for pressing said first and second bars to said drum surface; means for shifting said first and second support members along said guide slots against the supporting spring means for releasing said first and second bars from said drum surface; and stopping means disposed near said drum surface for holding said first and second bars in position and thereby preventing the rotation of said bars when said support members are shifted by said shifting means.
 10. An apparatus according to claim 9 wherein; said drum surface is provided with first and second longitudinal grooves for accommodating said first and second bars respectively; and said stopping means has first and second stop pins for engaging said first and second bars respectively, whereupon said second bar may be released from said second stop pin when said second bar is inserted into said second groove.
 11. An apparatus according to claim 9, wherein said stopping means has an operable stop pin for holding said second bar until said reaRward end of said sheet is disposed below said second bar.
 12. An apparatus according to claim 11, wherein there is further provided: means for generating a signal upon detection of the position of the rearward end of said sheet; and means for releasing said operable stop pin from said second bar upon receipt of said detection signal.
 13. An apparatus according to claim 9, wherein there is further provided a roll for delivering said sheet from the drum, said roll being connected to said shifting means and adapted to be frictionally pressed to said drum surface when said shifting means shifts said support members.
 14. An apparatus according to claim 9, wherein said shifting means includes: operating spring means for urging said first and second support members against said supporting spring means when said support members are shifted; and actuating means for releasing said shifting means from said first and second support members against said operating spring means.
 15. An apparatus according to claim 9, wherein at least one of, said drum, and said bars, is magnetically polarized. 